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This work investigates a diesel engine operating with diesel oil containing 7% biodiesel (B7) and hydrous ethanol with concentrations varying from 5% to 30%. The experiments were conducted in a 49 kW diesel power generator, equipped with an electronic ethanol injection unit installed in the intake manifold and without any modifications in the diesel oil injection system. The results showed a decrease of in-cylinder pressure and net heat release rate with the use of ethanol at low loads and an increase at high loads, in comparison with B7. Increasing ethanol injection caused increased ignition delay and decreased combustion duration. Fuel conversion efficiency was raised up to 13% with the use of ethanol. The use of 30% ethanol in the fuel caused a reduction of carbon dioxide (CO2) emissions up to 12% and nitric oxide (NO) up to 53%. Carbon monoxide (CO), total hydrocarbons (THC) and oxides of nitrogen (NOX) emissions increased with ethanol addition. The replacement of 20% of diesel fuel by ethanol showed the lowest penalties on NOX emissions.

The effects of fuel blends containing 5, 10 and 15 wt. % of anhydrous ethanol in diesel oil with 7% of biodiesel (B7) on performance, emissions and combustion characteristics of a diesel power generator are investigated. The engine was tested with its original configuration, with the fuel blends directly injected into the combustion chamber, and the applied load varied from 5 to 37.5 kW. The results were compared with standard B7 operation, and showed that in in-cylinder peak pressure and heat release rate were decreased at low loads and increased at high loads with the use of ethanol. Increasing ethanol concentration caused increased ignition delay, decreased combustion duration and reduced exhaust gas temperature. The use of ethanol decreased carbon dioxide (CO 2) emissions, up to 8.6% lower than B7. Carbon monoxide (CO), total hydrocarbons (THC) and oxides of nitrogen (NO X) emissions showed different behavior, depending on load and ethanol concentration.

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